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Sponsored Business Announcement: American Falls Dam project to begin in June, says Bureau of Reclamation

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American Falls Dam concrete spillway rehabilitation project is set to begin June 1, 2020. American Falls Dam, a 94-foot-high composite concrete and earth gravity-type dam on the Snake River in Power County, near the town of American Falls, will undergo maintenance and rehabilitation through 2020 and will resume June 2021.

The planned construction activities will address the need for replacement and repair of deteriorating concrete on the downstream portion of the dam, including the spillway, spillway gate operator decks, dam face, dam entrances and stilling basin structures, which have experienced degradation over 40 years in service.

Construction activities will consist of the hydro demolition, cutting, removal, and replacement of existing damaged concrete and reinforcing on these components, and replacement of the existing drain grate in the stilling basin. Reclamation awarded the construction contract on Aug. 28, 2019, to Winspear Construction, LLC, a service-disabled veteran-owned small business based in Boise.

Residents and visitors can expect to experience increased traffic supporting construction activities on State Highway 39 and within the city of American Falls traveling to and from the worksite. At this time, traffic restrictions or road closures are not anticipated. Reclamation anticipated a need for the closure of westbound SH-39 and the implementation of intermittent traffic restrictions on eastbound SH-39 for extended periods during construction in 2020 and 2021. Based on the contractor’s proposed work plan, which includes alternate access to the worksite, traffic control on SH-39 will not be necessary.

Given its size and location relative to other Reclamation facilities located throughout the upper Snake River storage system, American Falls Reservoir is heavily relied upon for the delivery of water for irrigation purposes. Going into each irrigation season, American Falls Reservoir is typically full or near full, with water receding as the irrigation season progresses. Reclamation plans to operate American Falls Reservoir through the two-year (2020-2021) construction period, consistent with previous years. Up-to-date water storage conditions in American Falls Reservoir and discharges from American Falls Dam can be found at the project webpage identified below.

During construction, effects to recreation are anticipated to be minimal, short-term and limited to the construction period. Parking access at the West Wall will be limited for the contractor staging area. The public will continue to have access to the west side beach from the West Boat Ramp.

Reclamation has developed a Water Quality Restoration Plan that can be found within the final Environmental Assessment to monitor and mitigate water quality issues. Reclamation has been actively working and will continue to work with Idaho Department of Environmental Quality, Idaho Power Company, and Idaho Department of Fish and Game throughout construction to monitor and mitigate water quality issues.

The final Environmental Assessment and Finding of No Significant Impact was completed on May 20, 2019, in accordance with the National Environmental Policy Act. A supplemental information report is being prepared and anticipated to be completed before construction begins June 1, 2020. For up-to-date information, go to